The present invention relates-to a producibility improver for poultry and method of improving producibility for poultry.
To date, various means have been employed to improve producibility for poultry. For example, there has been known a method in which an antibiotic is in used as an animal growth improver; however, there arise such problems as the safety and economy of the eggs and chicken meat produced. In addition, there is known a technique concerning a method of giving a specified feed for laying hens in a specified time zone daily; however, it lacks practical applicability because enormous time and labor are required to meet the strict nutritional control of a feed and time management of a supplying feed.
Also, with regard to storage methods for retaining freshness and the like, there have been known some methods, including a method of storing chicken eggs under a given temperature range; a method of storing a rapidly frozen food under freezing in a package material of high capacity for gas barrier; a method of using a freshness-retaining package for edible chickens, the package comprising a particular package container; a method of preventing lowering of the freshness of shell eggs by using a carbon dioxide-generating agent; and a method of immersing a poultry product in a particular fermented seasoning. However, these methods are economically disadvantageous in that a storage equipment or implementation of an apparatus for preparing a package material is necessitated. Also, there arise other problems, including deterioration of the natural taste of poultry meat when immersed in a fermented seasoning.
In addition, regarding the production of chicken eggs containing a highly unsaturated fatty acid, Japanese Patent Laid-Open No. Hei 5-292853 discloses a method for producing poultry eggs containing a highly unsaturated fatty acid wherein poultry for egg collection are bred with subcutaneously inoculating a fat and oil containing a highly unsaturated fatty acid thereto; Japanese Patent Laid-Open No. Hei 7-227221 discloses a method of using a feed composition containing a specified fatty acid source; Japanese Patent Laid-Open No. Hei in 118-80164 discloses a method for producing edible bird eggs comprising allowing female birds to take linseeds, thereby allowing the female birds to lay eggs containing eicosapentaenoic acid or docosapentaenoic acid; and Japanese Patent No. 2558050 discloses a chicken feed wherein a powder containing eicosapentaenoic acid or docosapentaenoic acid is mixed with a feed to prevent decrease in a rate of egg production. Although these techniques concern methods for producing chicken eggs enriched with a hCghly unsaturated fatty acid, there arise problems in that the highly unsaturated fatty acid in chicken eggs during chicken egg storage is unstable because the highly unsaturated fatty acids tend to be oxidized at carbon-carbon double bonds, and have poor storage stability.
On the other hand, there have been known some techniques in which a degradation product of a polysaccharide is added to a mammalian or bird feed. Japanese Patent Laid-Open No. Hei 8-099884 reports that a degradation product of a polysaccharide, as well as in combination with tannin, has been effective in suppressing the growth of gram-negative bacteria. Japanese Patent Laid-Open No. Hei 6-329548 reports that an enzymatically degraded product of guar gum is added to a livestock feed, promoting bowel movement, thereby giving prophylactic and therapeutic effects on diarrhea and the like. In addition, Japanese Patent Laid-Open No. Hei 10-201428 discloses a mineral absorption-promoting feed composition containing galactomannan treated to have a lower molecular weight. However, none of these techniques are involved with improvement of the producibility of laying hens bred for the purpose of producing chicken eggs and the producibility of edible chickens bred for the purpose of producing chicken meat.
As a result of intensive studies, the present inventors have found that a polymannose having a specified molecular weight distribution, a composition comprising the polymannose and the polyphenol compound, or a compound firther comprising delipidated rice bran has an remarkable action of improving the producibility for poultry. The present invention has been perfected thereby.
Specifically, the present invention relates to:
(1) a producibility improver for poultry, comprising a polymannose having a molecular weight distribution in which a polymannose having the molecular weights ranging from 1.8xc3x97103 to 1.8xc3x97105 accounts for 70% or more;
(2) a producibility improver for poultry, comprising a polymannose having a molecular weight distribution in which a polymannose having the molecular weights ranging from 1.8xc3x97103 to 1.8xc3x97105 accounts for 70% or more, and a polyphenol compound;
(3) a producibility improver for poultry, comprising a polymannose having a molecular weight distribution in which a polymarnose having the molecular weights ranging from 1.8xc3x97103 to 1.8xc3x97105 accounts for 70% or more, a polyphenol compound, and a delipidated rice bran; and
(4) a method of improving producibility for laying hens or edible chicken, using the producibility improver of any one of items (1) to (3) above.